I know that you want an answer here, but this finding is actually very interesting to me. Have you seen this seed germinate in an aquatic situation?

Does this lake dry out on a seasonal or decadal basis?

Do migratory birds visit this lake consistently?

I value your question greatly.

Hi Drew, to me they are not seeds but rather eggs of some aquatic insects. See they are placed almost in a row... I know that Aeshna viridis usually lays eggs on Stratiotes, but I have never seen them... Anyway I would vote for insects...

Best,

MIchal

Including Stratiotes aloides

http://commons.wikimedia.org/wiki/File:Aeshna_viridis_f1.JPG

Good call about the extremely straight row, I should have picked up on that.

Thanks Michal. I think you're right and I am wondering if they are indeed a type of dragonfly egg. What put me off before was the two 'roots' that stem from each egg, as I was not sure whether insect eggs had or developed such a feature, but that is my ignorance. Having investigated further, dragonfly eggs laid endophytically are typically spindle shaped, much longer than wide, very similar to those photographed. Given that there were numerous dragonfly and damselfly exuviae about, it makes sense. A paper (see link) I also found shows them deposited in similar rows too. For pure interest I also attach a photo of a dragonfly I found just emerging on the same day of survey.

http://entomology.kiev.ua/files/Matushkina.pdf

Hello Drew,

I have shown your pictures to my colleague, who is aquatic entomologist and he identified the eggs as laid by the water bug Ranatra linearis. If you google for "Ranatra linearis eggs" you will find a few pictures. So the mystery is solved :-)

Best,

Michal

Nice work Michal. The mystery is now solved like you said. I have looked at the photos and read that the two tubes running from the eggs provide oxygen.